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5. LINKING TO AN ACPU AND AN AJ71 PT3243
MELSEC-A
5.7.2
Precautions when programming
(1)
For communications with remote terminal modules linked to the
AJ71 PT32-S3, always turn
ON
the AJ71 PT32-S3 communications start
signal Y(n+28) before executing any instruction. If the communications
start signal is not turned ON, communications processing cannot be
done.
(2) Transmission to a remote terminal module cannot be done if the request-
to-send signal previously assigned to the same module remains
ON.
Use the send-completed signal to confirm that the previous transmission
is completed. Then, reset the request-to-send signal before executing
transmission to the same remote terminal module.
Request-to-send signal Y(n+O)
_1
Transmission execution
Sendcompleted signal X(n+O)
Transmission is allowed
after the leading edge
of this signal.
(3) When the reset switch on the front of the A64RDC is moved for resetting,
the A64RDC returns to the initial state. Processing is executed with
defaults until new set data (such as conversion-enabled/disabled desig-
nation and averaging designation) is written to the buffer.
The reset switch ON-detection signal from the A64RDC should always
be read from the batch refresh received-data areas
of the master module
using the FROM instruction. Initial set data should be transmitted to the
A64RDC when the detection signal is turned ON.
A64RDC reset
3 -
flag
(x5)
Reset switch ONdetected
flag reset signal
("5)
Reset switch ON-detected
Initial setting data is written to the A64RDC
buffer again in scans after this.
5-26
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